Seal blank



June 14, 1955 G. A. CROSBY United States Patent 2,710,435 Patented June 14, 1955 ice SEAL BLANK George A. Crosby, Park Ridge, lll., assigner to Signode Steel Strapping Company, Chicago, Ill., a corporation of Delaware Application August 25, 1952, Serial No. 306,144

4 Claims. (Cl. 24-23) The present invention relates to an improved seal automatic magazine strapping machines of the type forming the subject matter of the copending applications of John H. Leslie II and George A. Crosby, Serial Nos. 48,448 and 134,526, led September 9, 1948 and December 22, 1949, respectively. In an automatic machine the strapping is fed from a coil and around a closed track to encircle the bundle. As the free or leading end of the strapping overlaps the portion of the strapping connected to the coil, it is automatically grasped and held. A seal blank, loaded into the folding and deforming jaws of the sealing mechanism from the machines storage magazine, is brought into joint forming position and its flanges are folded about the overlapped strapping portions. The machine then automatically pulls on that portion of the strap connected to the coil so as to shrink the strapping down about the bundle and to tension it. This means that the strapping must be pulled through the folded seal blank as it embraces the overlapping strapping portions.

It has been found that strapping of heavier gauges and strapping with relatively sharp cornered edges have a tendency to seize with the seal blank. Such seizing or binding between the strapping and the seal blank prevents proper tensioning of the strapping about the bundle and also has the tendency to move the seal blank, thereby disturbing its proper positioning in the sealing jaws and preventing the forming of a proper joint.

It is, therefore, the principal object of this invention to provide a novel seal blank which overcomes the objections levied against the prior art blanks and which will Work without any difficulty in a magazine type automatic strapping machine.

It is another object of this invention to provide a novel seal blank which may be folded about the overlapping strapping portions so that there can be relative sliding movement between the strapping portions and the seal blank.

It is another object of the present invention to provide a new and improved seal blank wherein the flanges attached to the back plate of the blank are formed in such manner that they bend at predetermined points.

Another object of the present invention is to provide a novel seal blank having the foregoing advantages which may be made in a single operation on a coining machine.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a perspective view of the novel seal blank of this invention;

Fig. 2 is an end view thereof;

Fig. 3 is a perspective view illustrating a first step in folding the seal blank anges about the overlapping strapping portions;

Fig. 4 is a perspective view illustrating a further step in folding the seal blank flanges about the overlapping strapping portions and shows the anges in about the" position they occupy before they are clamped against the strapping and the joint is formed; and

Fig. 5 is a perspective View of a completed joint made by a typical joint forming tool or a sealing mechanism such as that embodied in an automatic strapping machine.

In the drawing, the reference characters 10 and 12 indicate the overlapping strapping portions, and the reference character 14 indicates the seal blank as a whole. The blank 14 is formed as a single metallic piece witha back portion or back plate 16, the Width of which is equal to or only very slightly greater than the width of the strapping with which the seal blank is to be used. The back portion or back plate 16 is bounded along its parallel edges by a pair of integral anges 18 which when the blank is initially formed project diagonally outwardly from the back plate 16. The haring anges permit stacking or nesting of a large number of blanks in the seal magazine of a strapping tool or strapping machine.

A seal blank as described in the preceding paragraph has been in commercial use for a number of years.. In the formation of the joint the inner face of the back plate 16 is brought against the outer face of one of the pairs of overlapping strapping portions, for example the strapping portion 12. The flanges 18 are folded inwardly about the strapping, bending at the corners 20 between the anges 1S and the back plate 16. As the flanges 1S are folded against the exposed face of the strapping portion 10 the seal bends against the corners or edges of the strapping and movement of the strapping relative to the seal causes binding or seizing between them. The joint is completed by cutting and depressing tabs 22 along the marginal edges of the sandwich formed by the overlapping strapping portions and embracing seal to provide interlocking shoulders 24 which resist separation of the strapping portions under tensional forces.

With the prior art seal blank, the binding between the blank and the strapping portions makes such a seal impractical for use in automatic strapping machines of the type described in the hereinabove listed patent applications because proper tensioning of the strapping cannot always be obtained. This diilculty arises because the anges 18 tend to bend first at only the corners 20 and then as they are folded against the strapping they bend where they contact the strapping thus binding the strapping portions and the seal together.

The seal blank of this invention is made to bend along predetermined lines so thatwhen the flanges 18 are folded about the strapping portions 10 and 12 they do not bind against the edges or corners of the strapping. To this end the flanges 18 are each provided with a stock weakening crease 26 on its inner face along its Whole length and spaced outwardly from the corner 20 a distance approximately equal to two thicknesses of strapping. The crease 25 provides a line in the ange area which is thinner than the remainder of the seal blank stock and, therefore, a line along which that portion 28 of the flange lying outwardly of the crease 26 may bend relatively to the small inner area of the ilange. The crease 26 thus provides a line of easy bending as compared to the flat areas of the seal blank 14.

The seal blanks 14 may be made in a single operation on a conventional coining machine from sheets or strips of metal.

rEhe seal blank of this invention may be folded about the strapping by the same tools or sealing mechanisms as folded the prior art blanks; the bending in the seal itself is appreciably dilferent. lts use will be described in a typical strapping operation in an automatic strapping 3 machine of the type disclosed in the aforementioned patent applications.

ln such machines the seal blank is loaded into the folding and tab cutting jaws of the sealing mechanism from a magazine in which a quantity of nested seals are stored. strapping is trained about the bundle from a coil with the strapping portion lying against the bundle and inside the strapping portion .t2 which remains connected to the coil. The free end of the portion 1G is grasped and anchored.

The sealing mechanism is operated to fold the seal blank anges S inwardly. As they are folded inwardly they initially bend at the corners as shown in Fig. 3. As the anges 18 are continued to be folded inwardly about the strapping portions 1t) and l2, the outer ange portions 28 bend on the creases 26 (Fig. 4). it is evident that there is no sharp crimping or clamping of the strapping portions l@ and l2 between the back plate 16 and the inner faces of the flanges 1 8. instead, the bends are at the corners Z0 and along the creases 26 to provide curved portions 3G of the folded seal blank which extend around the corners and edges of the strapping.

When the seal has been folded to approximately the position of Fig. 4, the strapping portion 12 is pulled through the folded seal blank 14 and past the overlapped anchored portion 10 to shrink the strapping down onto the bundle and to apply the proper tension to it.

Lastly the sealing mechanism is operated to clamp the anges 18 firmly against the face of the strapping portion 10, and the tabs 22 are cut and depressed to the position shown in Fig. 5 to complete the joint, and the portion 12 is severed from the coil.

While the use of the seal blank 14 has been described in conjunction with an automatic strapping machine, it is to be understood that it may be used with other tools for forming joints in overlapped strapping portions.

While a preferred embodiment of the seal blank constituting this invention has been shown and described, it will be apparent that modifications and variations thereof may be made without departing from the underlying principles of the invention. It is, therefore, desired by the following claims to include within the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

What is claimed as new and desired to be secured by United States Letters Patent is:

l. A one-piece metallic seal blank for use in forming a joint between overlapping metallic strapping portions, comprising a back plate having a width substantially equal to the width of the strapping with which the blank is to be used, a pair of llange portions joined to said back plate along its side edges and extending diagonally outwardly therefrom. and a thin part on each ange portion extending the whole length thereof and parallel to said back plate edges and spaced therefrom a distance approximately equal to two thicknesses of strapping with Which the blank is to be used.

2. A one-piece metallic seal blank for use in forming a joint between overlapping metallic strapping portions, comprising a back plate having a width substantially equal to the width of the strapping with which the blank is to be used, a pair of llaring ange portions joined to said back plate along its side edges, and a stock thinning crease in each said frange portion extending the whole length thereof and parallel to said back plate edges and spaced therefrom a distance approximately equal to two thicknesses of strapping with which the blank is to be used.

3. /x one-piece metallic seal blank for use in forming a joint between overlapping metallic strapping portions, comprising a back plate having a width substantially equal to the width ofthe strapping with which the blank is to be used, a pair of ange portions joined to said back plate along its side edges and extending diagonally outwardly therefrom, and a stock weakening line on the inner face of each flange portion extending the entire length thereof and parallel to said back plate edges and spaced thererom a distance approximately equal to two thicknesses of strapping with which the blank is to be used.

'-l. A one-piece metallic seal blank for use in forming a joint between overlapping strapping portions wherein the blank when folded embraces the strapping portions, the blank being of the type having a back plate of a width substantially equal to the width of the strapping with which the blank is to be used, and a pair of ange portions joined to the back plate along its side edges and extending diagonally outwardly therefrom, characterized by a stock thinning and weakening crease on the inner face of each iiange portion extending the Whole length thereof parallel to the back plate edges, each crease being spaced from the adjacent back plate edge a distance approximately equal to two thicknesses of strapping with which the blank is to be used so that as the flange portions are folded inwardly toward each other they will fold along their junctures with the back plate and then along said creases, with the adjacent corners of the strapping lying in said creases, whereby one piece of strapping may be moved relative to the other when the flanges are folded inwardly partially to embrace the strapping.

Leslie Dec. 6, 1921 Childress Feb. 18, 1941 

